The ignition modules are pretty notorious for going out. Some are on the side of the distributor, others are mounted on the firewall or fenderwell. Not sure on vans..
It has slowly gotten to where it doesn't want to run. It fires a little, but then quits. Is the module a 'quit right now' thing, or gradual? Yes I have changed the fuel filter.
Check the fuel pressure before you get too far into it.. I have replaced more fuel pumps/filters than ecm's. Like fifty to one..
Usually the module will shit when the engine is hot. Then after it cools off it will start back up. But it can do lots of other things too. will it start on ether? spray it in the throttle body and see if it keeps running longer than it does now. The fuel pump is a good possibility as said above if you have good spark or it runs on ether..